Daniel W. Drezner is professor of international politics at the Fletcher School of Law and Diplomacy at Tufts University and a senior editor at The National Interest. Prior to Fletcher, he taught at the University of Chicago and the University of Colorado at Boulder. Drezner has received fellowships from the German Marshall Fund of the United States, the Council on Foreign Relations, and Harvard University. He has previously held positions with Civic Education Project, the RAND Corporation, and the Treasury Department.

In this post, Tyler Cowen goes a long way towards explaining those reasons. His glosing paragraphs:

The funny thing is this: when Americans insist on total liberty against external molestation, it motivates both good responses and bad ones. It supports a libertarian desire for freedom against government abuse, but the same sentiments generate a lot of anti-liberal policies when it comes to immigration, foreign policy, torture, rendition, attitudes toward Muslims, executive power, and most generally treatment of "others." An insistence on zero molestation, zero risk, isn’t as pro-liberty as it appears in the isolated context of pat-downs. It leads us to impose a lot of costs on others, usually without thinking much about their rights.

The issue reminds me of the taxation and spending debates; many Americans want low taxes and high government spending, forever. For airline security, at times we want to treat it as a matter of mere law enforcement, to be handled by others, and one which should not inconvenience our daily lives or infringe on our rights. At the same time, so many Americans view airline security as a vital matter of foreign policy and indeed as part of a war. We own and promote this view and yet we are outraged when asked to behave as one might be expected to in a theater of war.

The main danger to liberty here is not the TSA but rather a set of American attitudes which, at the same time, take our current "war" both far too seriously and also not nearly seriously enough.

Overall, I’d like to see less posturing in these debates and more Thucydides.